1000+ Atomic Structure Multiple Choice Question Answer [Solved]

1. The angular momentum of the moving electron is equal to
A. $\sqrt{nh}$
B. $\raisebox{1ex}{$h^2$}\!\left/ \!\raisebox{-1ex}{$2\pi $}\right.$
C. $\raisebox{1ex}{$nh$}\!\left/ \!\raisebox{-1ex}{$\pi $}\right.$
D. $\raisebox{1ex}{$nh$}\!\left/ \!\raisebox{-1ex}{$2\pi $}\right.$
Answer : D

2. The size of nucleus is
A. ${10}^{-12} m$
B. ${10}^{-8} m$
C. ${10}^{-15} m$
D. ${10}^{-10} m$
Answer : C

3. $\beta$ rays are a stream of
A. He
B. electrons
C. positron
D. neutrons
Answer : B

4. Cathode rays contain a stream of
A. $n$
B. $r$
C. ${}_{+1}e^0$
D. ${}_{-1}e^0$
Answer : D

5. Isotones have same
A. mass number
B. nuclear mass
C. no. of neutrons
D. no. of electrons
Answer : C

6. The interrelationship between matter and energy was given by
A. Rutherford
B. Joule
C. de Broglie
D. Einstein
Answer : D

7. If value of h is taken as ${10}^{-34} kg m^2 se{c}^{-1}$, the de-Broglie wavelength of a particle of mass ${10}^{-31}$ having velocity ${10}^{9}cm se{c}^{-1}$ is
A. 0.01 m
B. 2 nm
C. 0.1 nm
D. $15\AA$
Answer : C

8. The maximum number of electrons in a sub-energy level is equal to
A. $4(2l+1)$
B. $2(2l+1)$
C. $2n^2$
D. $n^3$
Answer : B

9. The charge on an atom of ${}_{13}{}^{27}Al$ is
A. +40
B. +27
C. +14
D. Zero
Answer : D

10. The exchange of particles considered responsible for keeping the nucleons together are
A. meson
B. electron
C. positron
D. neutron
Answer : A

11. Charge on an electron was shown by
A. J. J. Thomson
B. Kirchoff
C. Ohm
D. M.Planck
Answer : A

12. Wave number is defined as
A. $\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$\lambda $}\right.$
B. $\raisebox{1ex}{${\lambda }^2$}\!\left/ \!\raisebox{-1ex}{$n\pi $}\right.$
C. $\raisebox{1ex}{$h$}\!\left/ \!\raisebox{-1ex}{$2\pi $}\right.$
D. $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$\lambda $}\right.$
Answer : D

13. The atomic number of an element having the valence shell electronic configuration $4s^{2}4p^6$ is
A. 35
B. 26
C. 23
D. 34
Answer : A

14. In an atom of hydrogen, which of the following orbitais has the lowest energy for an electron present in it?
A. 3r
B. 2p
C. 4p
D. 2s
Answer : B

15. The number of unpaired electrons in a chromic ion $C{r}^{+3}$ (atomic number 24) is
A. 6
B. 4
C. 3
D. 1
Answer : C

16. The number of unpaired electrons in fluorine atoms is/are
A. 4
B. 2
C. 1
D. 0
Answer : C

17. Among the following ions, which are has the highest paramagnetism?
A. $\left[Cr\right(H_{2}O{)}_6{]}^{+3}$
B. $\left[Fe\right(H_{2}O{)}_6{]}^{+2}$
C. $\left[Cu\right(H_{2}O{)}_6{]}^{+2}$
D. $\left[Zn\right(H_{2}O{)}_6{]}^{+2}$
Answer : B

18. Charge on fundamental particle neutrino is
A. 0
B. +1
C. -1
D. None of these
Answer : A

19. The number of unpaired electrons in the ground state of chromium is
A. 1
B. 6
C. 7
D. 2
Answer : B

20. Electronic configuration of $C{u}^{+}$ is
A. $\left[Ar\right]3d^9$
B. $\left[Ar\right]3d^{10}$
C. $\left[Ar\right]3d^{9}3s^2$
D. $\left[Ar\right]3d^{7}4s^{1}4p^1$
Answer : B

21. In the nucleus of ${}_{20}C{a}^{40}$ there are
A. 40 protons and 20 electrons
B. 20 protons and 40 electrons
C. 20 protons and 40 neutrons
D. 20 protons and 20 neutrons
Answer : D

22. The orbitals with maximum number of possible orientation is:
A. s
B. d
C. f
D. p
Answer : C

23. The possible values of l for an s orbital are
A. -1, +1
B. 0 to 2
C. -2 and + 1
D. 0
Answer : D

24. The number of neutrons in the deuterium atom is
A. 16
B. 3
C. 1
D. 0
Answer : C

25. When the electron is excited from K level to M level we get
A. $\gamma$- rays
B. cathode rays
C. continuous spectra
D. absorption spectra
Answer : D

26. The wavelength of an electron moving with a velocity $5\times {10}^{5}m se{c}^{-1} is (h=6.63 \times {10}^{-34} kg m^{2 }se{c}^{-1})$ 
A. $11.6 \times {10}^{-5}m$
B. $11.6 \times {10}^{-9}{m}^{-1}$
C. $14.6 \times {10}^{-5}m$
D. $1.46 \times {10}^{-9}m$
Answer : D

27. Argon is isoelectronic with
A. $M{g}^{++}$
B. $C{l}^{-}$
C. $B{r}^{-}$
D. $H^{+}$
Answer : B

28. Which of the following atoms has a non-spherical outermost orbital.
A. H
B. Li
C. Be
D. B
Answer : D

29. The velocity of a photon is
A. dependent on its wavelength
B. dependent on its source
C. equal to cube of its amplitude
D. independent of its wavelength
Answer : D

30. Davisson and Germer gave an experimental evidence for
A. wave nature of electron
B. particle nature of electron
C. particle nature of light
D. wave nature of light
Answer : D

31. The fundamental particle that has least mass is
A. meson
B. alpha-particle
C. electron
D. neutron
Answer : D

32. Which of the following has the highest mass?
A. Neutron
B. Alpha particle
C. Electron
D. Deuterium
Answer : B

33. For a given energy level the number of orbitals is equal to
A. $n^2$
B. $2l+1$
C. $4(2l+3)$
D. $\sqrt{2n^3}$
Answer : A

34. The maximum number of electrons that can be accommodated by an atom in g-sub-energy level are
A. 20
B. 25
C. 18
D. 12
Answer : C

35. No two electrons in an atom can have the same values of all four quantum numbers according to
A. Hund's rules
B. Flemming rule
C. Pauli's exclusion principle
D. Bohr theory
Answer : C

36. Frequency of the wave having wave number $20000 c{m}^{-1}$ is
A. $6\times {10}^{12} se{c}^{-1}$
B. $6\times {10}^{14} se{c}^{-1}$
C. $3\times {10}^{14}MHz$
D. $4\times {10}^{6}Hz$
Answer : B

37. The number of neutrons present in ${}_{19}{}^{39}K$ are
A. 28
B. 39
C. 20
D. 19
Answer : C

38. The corect set of quantum numbers for the impaired electron of fluorine atom is
A.

n	l	m
2	1	0

B.

n	l	m
2	1	1

C.

n	l	m
3	1	1

D.

n	l	m
3	0	0

Answer : B

39. In the case of atomic spectrum of hydrogen which series of lines lie in the visible region?
A. Balmer
B. Paschen 
C. Pfund
D. None of these
Answer : B

40. The atomic structure of an atom of an element is Is $1s^2, 2s^{2}2p^6, 3s^{2}3p^6$. The element is
A. Cl-35
B. S-32
C. N-18
D. O-16
Answer : A

41. The correct set of quantum numbers for the impaired electron of fluorine atom is
A.

n	l	m
2	1	0

B.

n	l	m
2	1	1

C.

n	l	m
3	1	1

D.

n	l	m
3	0	0

Answer : B

42. A dipositive ion $Z^{++}$ has $2e^{-}$ in the K shell, 8 e~ s in the L shell and $8e^{-}$ in the M shell. Atomic number of Z is
A. 19
B. 20
C. 16
D. 15
Answer : B

43. Which elements is represented by the following electronic configuration?

A. Nitrogen
B. Oxygen
C. Fluorine
D. Neon
Answer : C

44. The ion that is isoelectronic with CO is
A. $C{N}^{-}$
B. ${O_2}^{+}$
C. ${O_2}^{-}$
D. ${N_2}^{+}$
Answer : A

45. The relationship between energy of a radiation and its frequency was given by
A. Planck
B. Rutherford
C. Einstein
D. Joule
Answer : C

46. Mass of positron is the same to that of
A. proton
B. meson
C. electron
D. neutron
Answer : C

47. Which of the following weighs the least?
A. 1 g of $C{O}_2$
B. 2 litres of $C{O}_2$ at N.T.P.
C. $3.01\times {10}^{11}$ molecules of $C{O}_2$
D. $3.01\times {10}^{22}$ atoms of carbon
Answer : A

48. The wavelength of an electron
A. is equal to that of light
B. remains constant with velocity
C. decreases with an increasing velocity
D. increases with an decreasing velocity
Answer : C

49. Isotopes have different
A. arrangement of electrons
B. no. of P and e'
C. no. of neutrons
D. no. of electrons
Answer : C

50. Bohr's concept of the orbit in an atom was contradicted by
A. de Broglie relationship
B. Uncertainty principle
C. Planck's hypothesis
D. Hund's rule
Answer : B